JuliusBrussee/caveman · error · Error

assembly slot id must be non-empty and unique: ${JSON.string

Error message

assembly slot id must be non-empty and unique: ${JSON.stringify(slot.id)}

What it means

Error "assembly slot id must be non-empty and unique: ${JSON.stringify(slot.id)}" thrown in JuliusBrussee/caveman.

Source

Thrown at packages/sdk/typescript/src/index.ts:1816

const assemblyHashLedgers = new WeakMap<Cave, Map<string, string>>();
const assemblyRequestHeaders = new WeakMap<object, string>();

function assemble(cave: Cave, options: AssembleOptions): AssemblyResult {
  const provider = options.provider.trim().toLowerCase();
  const emitCacheHints = options.emitCacheHints ?? "gateway";
  if (!options.model || !options.sessionId) throw new Error("assemble requires model and sessionId");
  if (!["gateway", "self", "none"].includes(emitCacheHints)) {
    throw new Error(`unknown emitCacheHints value ${JSON.stringify(emitCacheHints)}`);
  }

  const ids = new Set<string>();
  let ledger = assemblyHashLedgers.get(cave);
  if (!ledger) {
    ledger = new Map<string, string>();
    assemblyHashLedgers.set(cave, ledger);
  }
  const normalized = options.slots.map((slot) => {
    if (!slot.id || ids.has(slot.id)) throw new Error(`assembly slot id must be non-empty and unique: ${JSON.stringify(slot.id)}`);
    ids.add(slot.id);
    if (!["stable", "session", "volatile"].includes(slot.stability)) {
      throw new Error(`assembly slot ${JSON.stringify(slot.id)} has unknown stability ${JSON.stringify(slot.stability)}`);
    }
    let contentJSON: string;
    try {
      contentJSON = canonicalJSON(slot.content);
    } catch {
      throw new Error(`assembly slot ${JSON.stringify(slot.id)} content is not JSON-serializable`);
    }
    const contentHash = sha256Hex(contentJSON);
    if (slot.stability !== "volatile") {
      const key = `${options.sessionId}\0${slot.id}`;
      const previous = ledger.get(key);
      if (previous !== undefined && previous !== contentHash) throw new AssemblyStabilityError(slot.id);
      ledger.set(key, contentHash);
    }
    return { ...slot, content: JSON.parse(contentJSON) as unknown };

View on GitHub (pinned to 27d5a3981a)

Solutions

1. Give each assembly slot a non-empty, unique id.

When it happens

Trigger: Thrown at packages/sdk/typescript/src/index.ts:1816 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of JuliusBrussee/caveman@27d5a3981a (2026-08-15). Data as JSON: /api/errors/e78121bd4e925f2e. Report an issue: GitHub.